Fuel antiknock



United States Patent FUEL ANTIKNOCK John D. Bartleson, Franklin, Michassignor to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application August 13, 1953, Serial No. 374,154

8 Claims. 01. 44-69 This invention relates to the improvement oforganolead material, and in particular to adjuvants for tetraethylleadand tetraethyllead-containing compositions.

Organolead compounds such as tetraphenyllead, tetramethyllead,tetraethyllead, dimethyldiethyllead, and the like have long been knownas antiknock agents for fuel for spark ignition type internal combustionengines. Of such materials, however, only tetraethyllead has attainedcommercial success because of its eflicacious attributes. Likewise, ithas long been known that the effective utilization of such antiknockagents is enhanced by providing antiknock fluids which consist oforganic halogen compounds in admixture with an organolead compound.

Organolead compounds suffer one disadvantage, particularly duringstorage, handling, and blending operations, namely, their inherentinstability. Thus, tetraethyllead and related compounds are susceptibleof deterioration which is largely dependent upon the nature of theenvironment. For example, it has been found that organolead antiknockagents and antiknock fluids containing the same, when in contact withcertain metals, such as copper and copper-containing alloys, tend todeteriorate, even in a reducing atmosphere. Such deterio ration ispostulated to result from an adverse catalytic activity exhibited bysuch metals. In other words, it is generally believed that copper andlike metals act as self-perpetuating decomposition accelerators. Anothercondition enhancing the deterioration of such antiknock agents iscontact with air. It is generally believed that atmosphericconstituents, notably oxygen and ozone, tend to oxidize one or more ofthe lead-to-carbon bonds with the formation of insoluble decompositionproducts. Under these conditions there contemporaneously occurs a colorchange in the dyestufi normally present in antiknock fluids such thatthe visual identification of the product frequently becomes diflicult,if not impossible. Organolead antiknock agents are likewise decomposedon exposure to strong light, particularly sunlight. In this case thedecomposition is attributed to the catalytic decomposition of theorganolead compounds'by ultra-violet light. It is apparent, therefore,that the exposure of tetraethyllead and tetarethyllead-containingcompositions to any or all of the above environments results in a numberof operational difliculties, including loss of antiknock efiectiveness,the formation of sludge and other types of sediment, and the like. 7

When organolead-containing compositions are utilized in internalcombustion engines, other difliculties are frequently encountered. Forexample, in spite of the high degree of efiiciency of the normalscavenger complement in antiknock fluids, the accumulation of enginedeposits in the engine cannot be entirely prevented. Such deposition isparticularly prevalent when spark ignition engines are operated underconditions of low speed and light load such as encountered inmetropolitan driving conditions. As a result of notable improvements infuel antiknock quality which have been made in recent years, suchdeposits present but a few minor problems in low Patented June 4, 1957compression engines. However, because of the trend in the automotiveindustry of utilizing high compression engines in passenger cars andtrucks, the accumulation of deposits results in a number of relativelyserious problems, including increased detonation, deposit-inducedautoignition or wild ping, spark plug fouling, reduction in exhaustvalve life, and the like.

Of the problems previously enumerated, those of wild ping, spark plugfouling, and reduced exhaust valve life are of considerable concern tothe automotive industry. This results from the fact that each time thelead concentration in the fuel is raised to coincide with increases incompression ratio to eliminate detonation, the magnitude of one or moreof these problems generally increases. As a result, there is a paramountneed existing for a new and improved method for altering the physicaland chemical characteristics of deposits and for modifying thecombustion process such that the well-known detrimental effects of thepreviously described depositinduced engine phenomena can be markedlysuppressed or be eliminated.

It is, therefore, an object of this invention to provide adjuvants fororganolead compounds. It is likewise an object of this invention toprovide means of improving compositions such as antiknock fluids andfuels which contain organolead antiknock agents. Similarly, theprovision of improved organolead compositions is another object of thisinvention. A particular object of this invention is to provide improvedtetraethyllead-containing fuels, especially those for use in sparkignition type internal combustion engines. In addition, an object ofthis invention is to provide methods of improving antiknock fluids suchthat during compounding, storage, and blending operations such materialsare stabilized against the adverse eiiects of deteriorativeenvironments. An additional object of the instant invention is toprovide means of obviating deposit-induced phenomena of the characterdescribed hereinbefore. Other important objects of this invention willbe apparent from the discussion hereinafter.

It has now been found that the above and other objects of this inventionare attained by providing compositions of matter adapted for use asadditives to fuel for spark-fired internal combustion engines comprisingan organolead antiknock agent, and in quantity sufficient to stabilizeor improve said agent, a metallic deriva tive of a product obtained byreaction between a phosphorus sulfide and an organic compound in whichat least one carbon atom is substituted with at least one univalentradical composed solely of a group VI-B element and hydrogen. Suchorganic compounds can be aliphatic, alicyclic, or aromatic so long asthey contain at least one univalent radical selected from the groupconsisting of hydroxyl, sulfhydryl, selenohydryl, and tellurohydryl. Inother words, the organic compounds used to form the intermediate fromwhich my organolead adjuvants are prepared consist of such compounds asalcohols, mercaptans, seleno alcohols, telluro alcohols, phenol,thiophenols, seleno phenols, and telluro phenols as Well as compoundscontaining mixtures of the several group VI-B containing functionalradicals as defined hereinabove. For the sake of conciseness suchmaterials are termed hereinafter as the organic reactants.

It will be apparent that the organolead adjuvants of this invention aremost readily prepared in two steps. The first step consists of preparinga product of a phosphorus sulfide and an organic reactant of the typedescribed hereinbefore. Depending upon the nature of the materialsemployed as Well as the reaction conditions, the product of thisreaction can be used in toto for the preparation of my metallicderivatives, or it can be subjected to intermediate treatment, as willbecome apparent from the related materials which are tridiscussionhereinafter. The second step in the preparation of my adjuvants consistsof reacting a salt of the desired metal with the above intermediatematerial.

' The organic reactant used to prepare the reaction products used asintermediates in the preparation of my adjuvan'ts can be a monohydric orpolyhydric alcohol.

-Typical alcohols so used are exemplified by the alkyl alcohols, alkenylalcohols, alkynl alcohols, cycloalkyl alcohols and cycloalkenylalcohols. In other words, I can prepare the intermediate products forthe preparation of my adjuvants from any of the monohydric or polyhydricalcohols known in the art as aliphatic or alicyclic alcohols. Morespecifically, the alkyl alcohols, which preferably should contain from 1to about 20 carbon atoms, are illustrated by a methanol, ethanol,propanol, isopropanol, and likewise the various straight and branchedchain alkyl alcohols exemplified by the several butyl, amyl, hexyl,heptyl, octyl, and like alcohols up to and including about eicosyl.Similarly, recourse can be made to comparable glycols, such as ethyleneglycol, propylene glycol, butylene glycol, and the like, as well as ortetra-substituted hydroxyl-containing organic reactants. The alkenylalcohols are typified by such substances as allyl alcohol, crotylalcohol and similar substances which contain at least onecarbon-t-o-carbon double bond in the organic residue. In this embodimentit is preferable to utilize alkenyl alcohols containing from 3 to about20 carbon atoms. The alkynl alcohols which can be used in preparing theintermediate products for the preparation of my adjuvants of thisinvention are illustrated by such materials as propynol, butynol,butyndiol, pentyndiol, and the like in which the straight or branchedcarbon chain containing at least one acetylenic linkage contains from 3to about 20 carbon atoms. Such compounds as cyclohexanol,methylcyclohexanol, diethylcyclohexanol,a-hydroxy-2,3,4,5,6,7,8-heptahydronaphthalene,B-hydroxyl,3,4,5,6,7,S-heptahyd-ronaphthalene, and analogous materialsare illustrative of cycloalkyl alcohols; that is, alcohols in which acycloalkyl nucleus is substituted with at least one hydroxyl function.In general, such materials should preferably contain from 6 to about 30carbon atoms in the molecule. Typical cycloalkenyl alcohols include theseveral cyclohexenols, cyclohexenediols, and like materials whichpreferably contain from to about 30 carbon atoms in the molecule.

It will be apparent to one skilled in the art that thiols, frequentlytermed mercaptans, are substantially analogous to alcohols.Consequently, in preparing the adjuvant intermediates of my inventionrecourse can be made to substances differing from the above-describedalcohols only to the extent that the hydroxyl group is replaced by a.sulfhydryl group. Thus, the organic reactant used to prepare theintermediate products for the preparation of my adjuvants can beexemplified by such compounds as methyl mercaptan, ethyl mercaptan,propyl mercaptan, isopropyl mercaptan, 1,2-ethane dithiol, allylmercaptan, cyclohexyl mercaptan, cyclohexene thiol, and analogouscompounds. In general, it is preferable to utilize mercaptans whichcontain up to about 30 carbon atoms in the molecule.

As indicated hereinbefore, both seleno alcohols and telluro alcohols canbe used as organic reactants in preparing the adjuvant intermediates ofthis invention. It will be appreciated that these substances aresubstantially analogous to alcohols with the exception that the hydroxylfunction is replaced either by a seleno hydryl group or a telluro hydrylgroup. As in the case of the mercaptans, it is preferable to employseleno alcohols and telluro alcohols which contain up to about 30 carbonatoms in the molecule.

, Because of their greater availability as articles of commerce, andtheir generally superior chemical and physical characteristics, thealcohols and mercaptans as above described are preferred over the selenoand telluro alcohols.

The aromatic organic reactants comprise phenols, thio phenols, selenophenols and telluro phenols.

The phenols utilized to prepare the adjuvant intermediates of thisinvention can be monohydric phenols, or polyhydric phenols. In theformer group I prefer to utilize such phenols as the diversemonohydroxy-substituted benzenes, naphthalenes, hydronaphthalenes, andthe like, as well as suitably substituted derivatives thereof. Thus, inpreparing my adjuvant intermediates I utilize such phenols as phenol,ortho-, meta-, and para cresols, xylols, such as l,2-dimethyl-3-hydroxybenzene, 1,2- diethyl-4-hydroxy benzene, l,3-dimethyl-2-hydroxy benzene,1,3-dipropyl-4-hydroxy benzene, 1,3-diisopropyl-5- hydroxy benzene,1,4-dimethyl-2-hydroxy benzene, thymol, carvacrol, mesitol and the like.The latter class of phenols which are used as the reaction products forthe preparation of my adjuvant intermediates, that is, the polyhydricphenols, is illustrated by such materials as pyrocatechol, resorcinol,hydroquinone, orcinol, hydroxyhydroquinone, phloroglucinol,butylphloroglucinol, l,2,3,4-tetrahydroxy benzene, l,2,3,5-tetrahydroxybenzene, l,2,4,5-tetrahydroxy benzene, pentahydroxy benzene, hexahydroxybenzene, 1,4-dihydroxy anthracene, 2,6-dihydroxy anthracene,4,5,9-trihydroxy anthracene, and the like.

Thiophenols are substantially analogous to phenols. Therefore,thiophenols corresponding to the phenols of the character describedhereinbefore can likewise be utilized as the intermediate products forthe preparation of my adjuvants. It will thus be apparent that both monoand polythiophenols can be utilized in this manner. Typical monofunctional thiophenols include such materials as the monosulfhydryl-substituted benzenes, naphthalenes, hydronaphthalenes, andthe like, as well as suitably substituted derivatives thereof. Morespecifically, such materials are exemplified by thiophenol,o-methylthiophenol, m-methylthiophenol, p-methylthiophenol,1,2-dimethylthiophenol, 1,3-dipropyl thiophenol, 1,4-diisopropylthiophenol, 1,3-dimethyl thiophenol, l-methyl- 4-ethyl thiophenol, andthe sulfur analogues of thymol, carvacrol, mesitol, and the like. Thepoly functional thiophenols are typified by 1,2-benzene dithiol;l,3-'benzene dithiol; 1,4-oenzene dithiol; 1-methyl-3,5-benzene dithiol;1,2,4-benzene trithiol; 1,3,5-benzene trithiol; -l,2,3,4-benzenetetrathiol; l,2,3,5-benzene tetrathiol; 1,2,4,5-benzene tetrathiol;benzene pentathiol; benzene hexathiol; 1,4-naphthalene dithiol, and thelike.

The aromatic organic reactants parallel the aliphatic and alicyclicorganic reactants insofar as the existence of seleno and telluroderivatives is concerned. That is to say, a somewhat scarce butnevertheless operative class .of reactants utilized in the preparationof my adjuvant intermediates comprises the seleno phenols and tellurophenols. It will be apparent that such compounds are substantiallyanalogous to the phenols and thiophcnols as above described with theexception that the one or more oxygenor sulfur-containing univalentradicals are replaced by the corresponding selenium and telluriumfunctions.

With the aromatic organic reactants, it is preferred to employ thephenols and thiophenols because of their lower 'cost, greateravailability, and their generally superior physical and chemicalattributes.

While the organic reactants described thus far generally representsingle chemical entities, it is frequently preferred to utilize as thereactant mixtures of the various materials, especially mixtures whichare readily available as articles of commerce. For example, typicalmixtures of organic compounds in which at least one carbon atom issubstitutedwith at least one univalent radical composed solely of agroup VI-B element and hydrogen are readily available as products fromfermentation and destructive distillation processes. In such cases, themixture consists of various alcohols. Other readily available mixturesintermediates include mixedmercaptans prepared bythe .interactionofmixed alkyl halides and the mono potassium salt of hydrogen sulfide inalcoholic solution, and mixed phenols obtained by heating mixtures ofaryl halides with dilute aqueous sodium hydroxide in the presence ofcopper salts in autoclaves at high temperatures. Other readily availablemixtures of organic reactants will become apparent to those skilled inthe art.

The phosphorus sulfide, the other prime reactant utilized asintermediate products for the preparation of my adjuvants, is preferablya reactive compound such as P285 (P4S1o) and P457. It is possible,however, to use certain of the other reported phosphorus sulfides underthe proper reaction conditions. Furthermore, another related reagentwhich can be successfully utilized in preparing my adjuvantintermediates is thiophosphoryl chloride, PSCls. It will likewise beapparent that under suitable conditions the various sulfides of arsenicor antimony can be similarly employed in forming organolead adjuvantintermediates for use in the present invention.

The intermediate products for the preparation of the adjuvants of thisinvention are readily prepared, the reaction generally requiring onlythe addition of a reactive phosphorus sulfide to the organic reactantand heating the mixture at a temperature at which the reaction takesplace as evidenced by the release of hydrogen sulfide until the reactionis substantially complete. The temperature of the reaction is largelydependent upon the nature of the individual reactants although,generally speaking, temperatures in the order of about 150 F. to about500 F. are saisfactory. In preparing some of the adjuvant intermediatesof my invention advantages are to be obtained by conducting the reactionunder super-atmospheric pressure which can be readily obtained byconducting the reaction in a closed vessel thereby taking advantage ofthe pressure resulting from the hydrogen sulfide so formed.

The reaction products, that is, the adjuvant intermediates of thisinvention, can be made in the presence of a diluent, if desired, whichmay or may not be subsequently removed. Such diluents are illustrated bysuch substances as kerosene, straight run and catalytically crackedhydrocarbons of the diesel fuel boiling range and the like.

The nature of the react-ion products forming the adjuvant intermediatesof this invention is contingent to a considerable degree upon the ratioof the reactants. That is to say, variations in the character of myadjuvant intermediates are achieved by utilizing different organicreactant-to-phosphorus sulfide atom ratios from between about 0.5 to 1to about to 1.

The reaction products used as the intermediate products for thepreparation of my adjuvants in accordance with this invention defyprecise chemical definition. For example, in Kosolapoif, OrganoPhosphorus Compounds, it is stated that there is very little reliableinformation about the products obtained when the ratio of alcohol orphenol to phosphorus pentasulfide differs from 4 to 1. Nevertheless, itis known that the magnitude of the organic reactant-to-phosphorussulfide ratio employed contributes a considerable efiect upon the natureof my adjuvant intermediates.

For example, when a low organic reactant-.to-phosphorus pentasulfideratio is employed, that is, a ratio from between about 0.5 to 1 to about2 to 1, it is generally believed that the reaction products contain asubstantial proportion of material containing the characteristicchemical bonding wherein A is either oxygen, sulfur, selenium ortellurium depending upon the nature of the organic reactant. On theother hand, when a high organic reactant to P285 ratio is employed,which ratio is from about 3 to l to about 10 to 1, it is presumed bythose skilled in the art that a sub- ,stantial proportion of the productcontains the characterwherein as before A represents a group VI-Belement. Thus, it would appear that although the reaction is believed toinvolve chemical combination between the hydrogen atom of the functionalgroup of the organic reactant and the phophorus sulfide, the reactionmechanism .is obscured by a number of concurrent effects including theoperation of the law of mass action, reaction kinetics, steric factorsas well as consideration of the nature of the prime reactants employed.It may well be that with certain pure starting materials and withcarefully controlled reaction conditions and concentrationssubstantially pure reaction products are obtainable. However, anadvantage inherent in this invention is the fact that it is notnecessary to prepare substantially pure materials and further that it isgenerally preferred to utilize the reaction product in toto as anadjuvant intermediate.

As indicated hereinbefore, the intermediate reaction product can be useddirectly for the formation of my adjuvants or it can be subjected to anintervening treatment. Such treatment consists of centrifugation orfiltration to remove any by-product, sludge, or other insoluble materialwhich under certain circumstances may be formed. Likewise, any excess ofvolatile reactant or a volatile diluent, if used, can be removed bydistillation. Furthermore, if desired the intermediate product can beextracted with a suitable solvent such as liquid propane or isopropanol,or can be contacted with an adsorbent such as activated charcoal, silicagel, activated clay or the like.

To prepare my organolead adjuvants the above-described intermediateproduct is reacted with a suitable salt of the desired metal. Forexample, the reaction inter mediate can be treated with an oxide,hydroxide, carbonate, or the like of the metal in question. It will beapparent, therefore, that a wide variety of metallic elements can beintroduced into the intermediate products thereby forming organoleadadjuvants for use in accordance with the present invention. However,generally speaking, a preferred embodiment of the instant inventionconsists of forming and hence utilizing reaction products containing analkali metal such as lithium, sodium, potassium and the like. Anadditional preferred embodiment of this invention resides in theutilization of alkaline earth metal-containing reaction products asorganolead adjuvants. Thus, by reacting the product obtained by reactionbetween a phosphorus sulfide and an organic reactant as above describedwith a suitable salt of such metals as magnesium, barium, calcium,strontium, and the like, efiicacious adjuvants of this invention areformed. It will be apparent, however, that other metallic elements canbe used to form suitable adjuvants. For example, tin, zinc, aluminum,arsenic and other metals higher in the electromotive series form highlydesirable additives for use in accomplishing the objects of thisinvention. The amount of the metallic salt used in preparing myadjuvants can be sufiicient to neutralize all or part of the acidity ofthe intermediate reaction product. The reaction itself is preferablycarried out at an elevated temperature in the range of about to 350 F.in order to complete the neutralization.

The particular conditions employed are naturally contingent upon thenature of the materials in question. By way of example, one generalmethod which can be used in forming my adjuvants is to conduct thereaction in the presence of a suitable diluent such as any of thetypical hydrocarbon solvents. Another modification used in preparing myadjuvants is to conduct the reaction at super-atmospheric pressure. Thisis found to be particularly eflicacious in the preparation of metallicadjuvants of this invention formed from metals, the bases of which arerelatively weak. Such is the case with alu- I described hereinbefore.

minum. On the other hand, the utilization of higher pressures isfrequently unnecessary particularly when the metallic element beingintroduced into my organolead adjuvants is capable of forming strongbases as in the case of the alkali metals.

Once the second step'of the reaction has been completed the reactionproduct can be used in toto as an organolead adjuvant or it can besubjected to conventional treatments of the type described hereinbefore.Thus, recourse can be made to such steps as solvent extraction,distillation, filtration, centrifugation, and the like.

While the preparation of my adjuvants has been described in terms of atwo-step process, it will be appreciated that under certaincircumstances, a one-step process can be used. That is to say, with manyof the prime reactants within the purview of this invention it ispossible to inter-mix suitable quantities with or without a diluent andsubject this mixture to thermal treatment until the reaction issubstantially complete. Further details regarding this method ofpreparing my adjuvants will be apparent to one skilled in the art. Theorganolead antiknock agent utilized in the compositions of matter of thepresent invention consists of an .organolead compound in which lead isdirectly bonded to carbon atoms. Such compounds are exemplified by thelead aryls such as tetraphenyllead, and the lead alkyls such astetramethyllead, tetraethyllead, tetrapropyllead, tetrabutyllead,dimethyldiethyllead, methyltriethyllead, and the like, as well asmixtures of such compounds. Because of the generally superiorcharacteristics of tetraethyllead and the ready accessibility thereof asan article of commerce, it constitutes a preferred embodiment of theorganolead antiknock agent utilized in accordance with the instantinvention.

With the various compositions within the scope of this invention theproportion of the metallic reaction product utilized in conjunction withan orgauolead compound is such that there is a total of from betweenabout 0.01 to about 0.80 theory of phosphorus. In this regard a theoryof phosphorus is defined as the amount of phosphorus theoreticallyrequired to react with the lead to form lead ortho phosphate, whichquantity is two atoms of phosphorus per three atoms of lead. However,generally speaking, it is sufficient to employ an amount of anorganolead adjuvant of this invention such that there is an amount ofphosphorus between about 0.05 and about 0.5 theory with the best overallresults usually being obtained with amounts of about 0.1 to about 0.2theory of phosphorus, the last-mentioned concentrations constituting apreferred embodiment.

Regarding many of the problems frequently associated with high octanequality fuel, an anomalous situation obtains. On one hand, an elfectiveadjuvant for organolead compounds should possess stability againstdeterioration in common environments, compatibility with the chemicalentities with which it comes in contact, and volatility so as to possessthe characteristic frequently re ferred to as engine inductability. Onthe other hand, the mere selection of a phosphorus compound to acquirethe optimum characteristics enumerated above does not necessarily assurethe efiectiveness of the compound in cornbatting such phenomena as sparkplug fouling, wild ping the like. It is entirely probable that someempirical relationship between physical properties and effectiveness inthe obviation of such problems exists, but as yet the state of the artdoes not contain a satisfactory relationship of this type. However. thephosphorus materials within the purview of this invention, for the mostpart, possess the requisite physical properties adapting them for use asorganolead adjuvants and at the same time are effective in obviatingengine problems of the type "It will be apparent that there exists anumber of variations in employing the adjuvants of this invention. For

example, a facet of this invention involves the provision of a mixtureof an organo'lead antiknock-agent such as a lead alkyl andametal-containing reaction product used as an adjuvant in accordancewith the present invention. In such a case, the resulting compositioncan -be blended with hydrocarbon (fuel of the gasoline boiling range toprovide an improved fuel composition which under certain circumstancesdoes not require the utilization of organic halogen-containing materialas a scavenger. It is believed that under these conditions the presenceof a quantity of phosphorus and sulfur as above described and chemicallybonded in accordance with the requirements of the metal-containingreaction products used as an adjuvant in this invention contributessufiicient scavenging action such that the amount and character ofdeposition in the engine are suitably controlled, notwithstanding thefact that lead phosphates genenally have high melting points. Likewise,in this embodiment of the instant invention the general storagecharacteristics of organolead compounds are frequently enhanced.

Of perhaps more practical importance is a second variant of thisinvention, namely the utilization of the aforesaid metal-containingreaction products in organolead-containing antiknock fluids. It is wellknown in the art that the most convenient means of marketing andblending organolead antiknock agents is in the form of an antiknockfluid which usually contains, in addition to the lead compound, one ormore organic bromine and/ or chlorine compounds and an organic dye foridentification purposes. On occasion such antiknock fluids likewise maycontain minor proportions of diluents, antioxidants, metal deactivatorsand the like. In line with the foregoing, therefore, a preferredembodiment of this invention involves providing improved antiknockfluids containing the requisite concentration of the above describedmetal-containning reaction products. Such improved antiknock fluidsgenerally do not require the presence of a solub'ilizing agent or astabilizer since the phosphorus compound itself is generallysufficiently miscible with the constituents of the antiknock fluid andimparts thereto a degree of stabilization. However, under someconditions additional benefits are to be derived by employing in theimproved antiknock fluids of this invention the necessary quantities ofsuch materials.

Still another variant of the present invention consists of providingimproved fuel compositions. These normally consist of hydrocarbons ofthe gasoline boiling range containing a minor proportion of theaforesaid antiknock fluids of the present invention. It will beappreciated that the quantity of the antiknock fluid of the presentinvention utilized in my improved fuel compositions is primarilycontingent upon the use for which the gasoline is intended. That is tosay, when the fuel is intended for use in automotive engines such aspassenger cars, trucks, buses and the like, an amount of any of myimproved antiknock fluids equivalent to a lead content in the gasolineof from between about 0.53 and about 3.17 grams of lead per gallon issatisfactory.

Thus, in the embodiments of this invention wherein I employtetraethyllead as an antiknock agent such concentrations are equivalentto from between about 0.5 and about 3 milliliters of the compound pergallon. 'With the advent of the more recent high compression ratiointernal combustion engines, however, it is becoming increasinglyapparent that benefits are to be derived by employing somewhat greaterconcentrations of the organslead material in automotive gasoline. Onthis basis, therefore, automotive fuels containing upto'about 4.75 gramsof lead per gallon are contemplated. In contrast, when the improvedantiknock fluids of the :present invention are utilized in fuel' foraviation engines somewhat higher concentrations are'employed. Generallyspeaking, amounts of leadup to about 6.34 grams of lead per gallon canbe utilized although somewhat lesser quantities are presently in vogue.In other words, inthe tetraethyllead-containing embodiments of thisinvention there can be present up to about 6 milliliters oftetraethyllead per gallon as an improved antiknock fluid of myinvention. Concentrations above these limits can be employed in bothmotor and aviation fuels, practical considerations being the primecriterion for establishing the upper concentration limit. As indicatedhereinabove, in all of the compositions of the present invention theamount of phosphorus is fixed-within the limits above described. Thus,in the preferred fuel embodiments of my invention there is present anamount of phosphorus as a metal-containing reaction product such thatthere is from about 0.1 to 0.2 theory of phosphorus. In preparing theimproved fuel compositions of this invention, it is usually necessaryonly to add the requisite quantity of the improved fluid to the fuel andby means of stirring, shaking or other means of physical agitationhomogeneous fuel compositions are provided. Although the simplest meansof preparing such fuels is to blend therewith the necessary quantity ofan improved antiknock fluid of this invention, it is possible to add aconventional antiknock fluid to the fuel and subsequently blendtherewith the necessary quantity of the metalcontaining reactionproduct. In addition to reversing this order of addition of conventionalantiknock fluids and metal-containing reaction products used as'adjuvants in accordance with this invention, another variant is toblend with the fuel each of the individual constituents of my antikn'ockfluids separately.

The following specific examples wherein parts and percentages are byweight are illustrative of the methods which can be employed inpreparing the adjuv-ants of this invention.

Example I To a suitable glass reaction vessel equipped with an electricheating mantle and a stirrer is added 250 parts of Z-ethylhexanol and750 parts 'of virgin gas oil. To this mixture is then added 222 parts ofphosphorus pentasulfide (P285). The temperature of the vessel is thenraised to 250 F. and maintained at this temperature for a period ofabout two hours while vigorously agitating the reactants. Uponcompletion of the reaction the prodnot is subjected to centrifugationand filtration so as to remove the minor quantities of undesirableproducts which are formed. To 500 parts of this product is added 200parts of lithium hydroxide and 200 parts of water. This mixture isheated to a temperature of 180 F. for 2 hours, after which time thetemperature is raised to 250 F. for an additional 2 hours. During thelatter period of heating air is passed through the reaction mixture soas to strip therefrom excess water. Upon completion of this step thereaction mixture is filtered while hot to remove minor quantities ofsolids which have formed.

Example II To a suitable glass reaction vessel equipped with an electricheating mantle and a stirrer is added 250 parts of Z-ethylhexanol and750 parts of virgin gas oil. To this mixture is then added 222 parts ofphosphorus pentasulfide (P285). The temperature of the vessel is thenraised to 250 F. and maintained at this temperature for a period ofabout two hours while vigorously agitating the reactants. Uponcompletion of the reaction the product is subjected to centrifugationand filtration so as to remove the minor quantities of undesirableproducts which are formed. To 500 parts of this product is added 110parts of freshly precipitated zinc oxide and 100 parts of water. Thismixture is then heated for 2 hours at 180 F. The temperature is thenraised to 250 F. for an additional 2 hours while contemporaneouslyblowing air through the reaction mixture. At the end of this time theproduct is filtered, preferably while hot.

10 Example 111 In a suitable reaction vessel are placed 149 parts ofamyl mercaptan and 222 parts of phosphorus heptasulfide (R156). Thetemperature of the reactants is then raised to 325 F. and maintained atthis temperature for four hours while continuously agitating themixture. At the end of this time the reaction mass is diluted with anequal volume of toluene. The solution is then allowed to stand forfifteen minutes during which time minor amounts of solid products havesettled to the bottom of the container. These are removed by subjectingthe entire product to filtration. To 500 parts of the filtrate is added250 parts of an aqueous solution of potassium hydroxide containing 40parts of the hydroxide per liter. The resulting mixture is then heatedfor 2 hours at a temperature of 180 F. and then for 2 more hours at atemperature of 250 F. while passing air through the mixture. After thistreatment it is preferable to filter the reaction products while hot.

The reactants and reaction conditions described in the previous specificexamples are merely illustrative. For example, by utilizing the aboveand similar reaction conditions it is possible to prepare suitableadjnvants by reaction a phosphorus sulfide such as P285, P48 and thelike with such organic reactants as abietyl alcohol, terpineol, amylmercaptan, p-hutyl thiophenol, and in turn the product with calciumoxide, or the hydroxides of tin, bianium, strontium, magnesium and thelike. Furthermore, as indicated previously it is possible to utilizethiophosphoryl chloride in forming the adjuvant intermediates of thisinvention. When this is done and a low organicreactant-to-thiophosphoryl chloride mole ratio is employed, hydrolytictreatment with hydrogen sulfide should follow the thermal step.Generally speaking, such low mole ratios are in the order of from about1 to 1 to 2 to 1, although minor deviations from these ratios can beutilized. When a high organic reactantto-thiophosphoryl chloride moleratio is employed such hydrolytic treatment is generally unnecessary. Insuch a case, however, it is frequently desirable to conduct the reactionin the presence of a hydrogen chloride acceptor such as amines,pyridines and the like.

To illustnate the elfectiveness of the improved antiknock fluids of thepresent invention consideration can be given to the problem of sparkplug fouling. In order to do this, recourse can be made to the followinggeneral test procedure utilizing a standard modern V-8 engine equippedwith overhead valves having a 3% bore, a 3 5 stroke, a 303.7 cubic inchdisplacement and a compression ratio of 7.25 to one equipped withcommercially available spark plugs. In order to establish a base linethis engine is operated in conjunction with an engine dynamometer on astandard commercial fuel containing 3 milliliters of tetraethyllead pergallon as conventional antiknock fluid containing 0.5 theory of bromineas ethylene dibromide and 1.0 theory of chlorine as ethylene dichloride.This is operated under a durability schedule used for spark plug depositaccumulation patterned after road conditions experienced in city drivingwhich are known to produce spark plug fouling. of the greatestmagnitude. Such operation is substantially continuous until a number ofspark plug failures is detected thereby establishing a quantitativemeasure of the degree of spark plug fouling which can be expressed inaverage hours to plug failure. The engine .is then freed from depositsand equipped with new spark plugs. The same procedure is repeated usingthe same fuel base stock to which is added an improved antiknock fluidof the present invention.

.By way of example, when 300 gallons of a petroleum hydrocarbon fuelavailable as an article of commerce is treated with 900 milliliters oftetraethyllead in a fluid containing tetraethyllead, 0.5 theory ofbromine as ethylene dibromide and 1.0 theory of chlorine as ethylenediber.

chloride, a suitable fuel is prepared for establishing a base line ofhours .to spark plug failure. When the standard V-8 engine describedhereinbefore is then operated on this homogeneous fuel composition it isfound that in an average time of about 34 hours 3 spark plug failureshave occurred.

In contrast, when a suitable quantity of the same fuel base stock istreated with an improved antiknock fluid of the present inventiongreatly enhanced spark plug life is obtained. For example, when 1000gallons of the same fuel base stock is treated with 3 liters oftetraethyllead as a fluid comprising 0.5 theory of bromine as ethylenedibromide, 1.0 theory of chlorine as ethylene dichloride, and 0.2 theoryof phosphorus as the strontium salt of a PSCls-amyl mercaptan reactionproduct, an improved fuel of the present invention results. Uponintimately mixing the aforementioned components the homogeneous fuelcomposition containing 3.0 milliliters of tetraethyllead per gallon issuitable for use in the above-described engine test procedure. It isfound that a substantial improvement in spark plug performance asevidenced by the greater period of continuous engine operation resultsfrom the utilization of such improved fuel of the present invention.That is to say, the average hours to three spark plug failures issubstantially in excess of the base line figure of 34 hours.

When'such adjuvants as the beryllium salt of P285- cardanol, the lithiumsalt of PzSs-terpineol, the zinc salt of PSCls-nonanol and the like areutilized in accordance with the present invention comparableeffectiveness regarding minimization of spark plug fouling is obtained.Without desiring to be bound by the following explanation regarding theenhanced effectiveness of the ad- -juvant intermediates of thisinvention, a tenable explanaall effectiveness of my adjuvantintermediates by facilitating decomposition at the proper instant in theengine cycle.

To still further illustrate the enhanced effectiveness of theorganolead-containing compositions of the present inventionconsideration can be given to the problem of wild ping. To demonstratethe effectiveness of my compositions in this regard, I can subject botha hydrocarbon fuel treated in accordance with this invention and anotherportion of the same hydrocarbon fuel treated with a conventionalantiknock mixture to a test procedure involving the use of asingle-cylinder CFR knock test engine equipped with an L-head cylinderand a wild ping counter which records the total number of wild pingswhich have occurred during the test periods. Such apparatus includes anextra spark plug used as an ionization gap which is installed in asecond opening in the combustion cham- A mechanical breaker switchdriven at camshaft speed is also provided which, when closed, makes thevwild ping counter inefiective for the duration of the normal flamein'the combustion chamber. The breaker is open for 80 crankshaft degreesbetween 70 B. T. C. (before top dead center) and 10 A. T. C. (after topdead center). by deposits reaches the ionization gap during this openperiod, the counter registers a wild ping regardless of the audiblemanifestations. During normal combustion with ignition timing at T. D.C. (top dead center) the flame front reaches the ionization gap at to 18A. T. C. during the period wherein the points are closed and no count ismade. The actual test procedure consists essentially of operating thetest engine initially having a clean combustion chamber under relativelymild cycling conditions for deposit formation until an equilibrium withregard to deposit-induced autoignition is reached.

The effect of fuels treated in accordance with the instant "inventionisdetermined by comparing the test results If a flame front induced earlyin the cycle 12 obtained using the fuel treated with a metal-containingreaction product with those obtained using a fuel treated with acOnVentiQnal antiknock mixture. Since the wild ping counter records thetotal number of wild pings which have occurred during the testprocedures a quantitative expression for the amount of deposit-inducedautoignition is the number of wild pings per hour of operation. Theeffectiveness of my improved fuel composition in virtually eliminatingdeposit-induced autoignition will be apparent from the followingspecific examples.

Example IV To gallons of a commercially available blend of straight run,catalytically cracked and polymer blending stocks was added andthoroughly mixed 300 milliliters of tetraethyllead as an antiknock fluidcomprising tetraethyllead, 0.5 theory of bromine as ethylene dibromide,and 1.0 theory of chlorine as ethylene dichloride. The resultinghomogeneous fuel composition was then utilized as the fuel in thepreviously designated single-cylinder laboratory test engine toformulate a base line of wild ping. It was found that there were wildpings per hour of engine operation.

Example V An improved antiknock fluid composition of the presentinvention is prepared by adding 0.1 theory of phosphorus as the productobtained by reaction between P285, 2-ethylhexanol, followed by reactionwith lithium hydroxide to milliliters of tetraethyllead as an antiknockfluid comprising tetraethyllead, 0.5 theory of bromine as ethylenedibromide, and 1.0 theory of chlorine as ethylene dichloride. Ahomogeneous fluid composition is obtained by intimately mixing theaforementioned components. The entire quantity of improved autiknockfluid composition so prepared is added to 50 gallons of a commerciallyavailable blend of straight run, catalytically cracked and polymerblending stocks. Upon mechanically agitating the resulting mixture ahomogeneous fuel composition is prepared. The laboratory single-cylindertest engine as described previously is then operated on this improvedfuel composition while contemporaneously determining the rate of wildpings as detected by the wild ping counter. utilization of an improvedantiknock fuel of the present invention greatly minimizes the rate ofwild pings expressed in wild pings per hour as contrasted with aconventional fuel which produces 135 wild pings per hour. Consequently,an improved fuel composition of this invention results in a substantialreduction in this depositinduced engine phenomenon.

The foregoing specific examples are merely illustrative of thebeneficial effects produced by the improved organolead-containingcompositions of the present invention. It will be apparent that it ispreferred to utilize such metallic reaction products as the sodium saltof PzSa-thiophenol, the magnesium salt of PS'I-blltfllflOl, the aluminumsalt of PSCls-amyl mercaptan and the like in high octane quality fuelbecause of the fact that most of the deposit-induced problems exist oncombustion of such fuels.

The superior effectiveness of the preferred embodiments of thisinvention, namely a metal-containing reaction product as definedhereinbefore, in the diminution of deposit-induced engine problems isfurther unexpected when considering the prime constituents phosphorusand sulfur which are contained therein. On the one hand, both sulfur andphosphorus compounds have heretofore been judiciously avoided as much aspossible in fuel because of their notorious deleterious effectsparticularly in the realm of organolead antagonism and the like. In

the case of sulfur, for example, refiners have long been resorting tovarious means of removing sulfur compounds from hydrocarbons of thegasoline boiling range because of their recognized deleterious etfectson antiknock ac- It is found that the 7 tivity, engine cleanliness,storage stability, and the like. However, the adjuvant intermediates ofthis inventi n possessing considerable proportions of phosphorus andsulfur do not bring about such deleterious effects. Furthermore, anothersurprising effect has been noted, namely the fact that the presence ofphosphorus-to-sulfur bonds produces a greater effectiveness regardingwild ping than that exhibited by compounds possessing either phosphorusor sulfur and likewise a mixture of phosphorusand sulfur-containingcompounds. This fact is evidenced by the findings that the presence ofadded sulfur in a conventional leaded fuel not only has no beneficialeffect on wild ping but actually results in an increase in thisphenomenon. By way of example, it was found that the addition of 5theories of sulfur as a mixture consisting of one theory of di-t-butyldisulfide, 2 theories of dibutyl sulfide and 2 theories of thiophene, amixture representative of the average sulfur constituents of petroleumhydrocarbon fuel, to a conventional gasoline containing 3 milliliters oftetraethyllead per gallon resulted in a wild ping rate of 93 wild pingsper hour. In contrast, the same fuel containing the same concentrationof tetraethyllead produced74 wild pings per hour. Thus, theincorporation of sulfur-containing compounds diiferent from thesulfur-containing adjuvants utilized in this invention resulted in awild ping rate amounting to 125 percent of the base line. That is tosay, the presence of sulfur-containing compounds generally increases therate of wild ping whereas the presence of a considerable amount ofsulfur when suitably bonded in accordance with the present inventionresults in a definite improvement in this deposit-induced phenomenon. Inview of the foregoing, therefore, the apparent conclusion to be reachedis that the chemical bonds between the two prime elements making up myadjuvant intermediates in some currently unexplainable manner produceenhanced effectiveness with regard to deposit-induced engine phenomenawithout resulting in secondary deleterious problems normally attributedto the presence of each of the elements when used separately or asmixtures of individual phosphorusand sulfur-containing compounds.

As indicated, an additional important advantage obtained from practicingthis invention is the fact that my adjuvants have little or noantagonistic effect upon the antiknock agent used in the fuel. In linewith the enhanced effectiveness of my organolead adjuvant intermediatesthis surprising benefit regarding a minimum of organoleaddestructiveness is perhaps associated with the degree of oxidativestability inherent in my metal-containing reaction products. In otherWords, it is not inconceivable that my organolead adjuvants are capableof decomposing at the proper instant in the engine cycle so as toexhibit the beneficial efiect regarding deposit-induced engine problemswhile at the same time decomposing at a time during the engine cyclesufliciently far removed from the point at which the organolead compoundexerts its beneficial antiknock activity.

Because of their adaptability the adjuvant intermediates of the presentinvention can be successfully utilized with any of the well knownorganolead antiknock agents as indicated hereinbefore. Likewise, insofaras the halide scavengers are concerned, the metal-containing reactionproduct used as an adjuvant in accordance with this invention can beemployed in antiknock fluids and fuels containing such materials asethylene dibromide, ethylene dichloride, mixed dibromotoluenes,tn'chlorobenzenes, and, in general, such organic halide scavengers asthose disclosed in U. S. 1,592,954; 1,668,022; 2,364,921; 2,398,281;2,479,900; 2,479,901; 2,479,902; 2,479,903; and 2,496,983. Likewise, theadjuvant intermediates of this invention can be used in conjunction withother well known motor fuel adjuvants such as antioxidants, organoleadstabilizers, organic dyes, solubilizers, and indeed with othercatalytically active materials frequently employed in fuel.

Having fully described thenature of the present invention, the needtherefor, and the best mode devised for carrying it out, it is notintended that this invention be limited except within the spirit andscope of the appended claims.

I claim:

1. An antiknock additive for use in hydrocarbon fuels of the gasolineboiling range, said additive comprising an organolead antiknock agentand .a metallic derivative of a product obtained by reaction between (1)an organic compound in which at least one carbon atom is substitutedwith at least one univalent radical composed solely of a group VI-Belement and hydrogen, said radical being bonded to said carbon .atomthrough said group VI-B element, said compound containing-only elementsselected from the group consisting of carbon, hydrogen, oxygen, sulfur,selenium, and tellurium, and (2) a phosphorus sulfide selected from thegroup consisting .of P285 and P487, said product being prepared byheating from about 0.5 to about 10 moles of said compound per mole ofsaid sulfide to a temperature at which hydrogen sulfide'is released,said metallic derivative being prepared by reacting said' product atatemperature in the range of about to 350 F. with an amount of a metallicbase selected from the group consisting of oxides, hydroxides, andcarbonates sufficient to neutralize at least a part of the acidity ofsaid product; said metallic derivative being present in said additive inamount such that the phosphorus-to-lead atom ratio is from about 0.02/ 3to about 1.6/3.

2. The additive of claim 1 further characterized in that the antiknockagent is a lead alkyl.

3. The additive of claim 1 further characterized in that the antiknockagent is tetraethyllead.

4. An antiknock additive for use in hydrocarbon fuels of the gasolineboiling range, said additive consisting essentially of tetraethyllead, ascavenging amount of or- :ganic halide material capable of reacting withthe lead during combustion in a spark ignition internal combustionengine to form volatile lead halide, said material containing onlyelements selected from the group consisting of bromine, chlorine,carbon, hydrogen, and oxygen; and a metallic derivative of a productobtained by reaction between (1) an organic compound in which at leastone carbon atom is substituted with at least one univalent radicalcomposed solely of a group VI-B element and hydrogen, said radical beingbonded to said carbon atom through said group VI-B element, saidcompound containing only elements selected from the group consisting ofcarbon, hydrogen, oxygen, sulfur, selenium, and tellurium, and (2) aphosphorus sulfide selected from the group consisting of P255 and P487,said product being prepared by heating from about 0.5 to about 10 molesof said compound per mole of said sulfide to a temperature at whichhydrogen sulfide is released, said metallic deriv,a tlve being preparedby reacting said product at a temperature in the range of about 180 to350 F. with an amount of a metallic base selected from the groupconsisting of oxides, hydroxides, and carbonates sufiicient toneutralize at least a part of the acidity of said product; said metallicderivative being present in said additive in amount such that thephosphorus-to-lead atom ratio is from about 0.02/3 to about 1.6/3.

5. The additive of claim 4 further characterized in that said scavengingamount of organic halide material is about 0.5 theory of bromine as abromohydrocarbon compound capable of reacting with the lead duringcombustion in .a spark ignition internal combustion engine to formvolatile lead bromide, and about 1.0 theory of chlorine as achlorohydrocarbon compound capable of reacting with the lead duringcombustion in a spark ignition internal combustion engine to formvolatile lead chloride.

6. Hydrocarbon fuel of the gasoline boiling range adapted for use asfuel for spark ignition internal combustion engines containing up toabout 6.34 :grams of metallic derivative of a product obtained byreaction between (1) an organic compound in which at least one carbonatom is substituted with at least one univalent radical composed solelyof a group VI-B element and hydrogen, said radical being bonded to saidcarbon atom through said group VI-B element, said compound containingonly elements selected from the group consisting of carbon, hydrogen,oxygen, sulfur, selenium, and tellurium, and (2) a phosphorus sulfideselected from the group consisting of P255 and P457, said product beingprepared by heating from about 0.5 to about 10 moles of said compoundper mole of said sulfide to a temperature at which hydrogen sulfide isreleased, said metallic derivative being prepared by reacting saidproduct at a temperature in the range of about 180 to 350 F. with anamount of a metallic base selected from the group consisting of oxides,hydroxides, and carbonates suflicient to neutralize at least a part ofthe acidity of said product; said metallic derivative being present insaid fuel in amount such that the phosphorus-to-lead atom ratio is fromabout 0.02/3 to about 1.6/3.

7. The hydrocarbon fuel composition of claim 6 further characterized inthat it contains from about 0.53 to about 4.75 grams of lead per gallonas tetraethyllead,

about 0.5 theory of bromine as a bromohydrocarbon compound capable ofreacting with the lead during combustion in a spark ignition internalcombustion engine to 'form volatile lead bromide, and about 1.0 theoryof chlorine as a chlorohydrocarbon compound capable of reacting with thelead during combustion in a spark ignition internal combustion engine toform volatile lead chloride.

8. The composition of claim 6 wherein the metal of said metallicderivative is selected from the group consisting of alkali and alkalineearth metals.

References Cited in the file of this patent UNITED STATES PATENTS RudelJune 19, 1945 Campbell Aug. 13, 1946 Bartleson Dec. 19, 1950 FOREIGNPATENTS Great Britain Nov. 26, 1952

6. HYDROCARBON FUEL OF THE GASOLINE BOILING RANGE ADAPTED FOR USE ASFUEL FOR SPARK IGNITION INTERNAL COMBUSTION ENGINES CONTAINING UP TOABOUT 6.34 GRAMS OF LEAD PER GALLON AS AN ORGANOLEAD ANTIKNOCK AGENT,AND A METALLIC DERIVATIVE OF A PRODUCT OBTAINED BY REACTION BETWEEN (1)AN ORGANIC COMPOUND IN WHICH AT LEAST ONE CARBON ATOMS IS SUBSTITUTEDWITH AT LEAST ONE UNIVALENT RADICAL COMPOSED SOLELY OF A GROUP VI-BELEMENT AND HYDROGEN, SAID RADICAL BEING BONDED TO SAID CARBON ATOMTHROUGH SAID GROUP VI-B ELEMENT, SAID COMPOUND CONTAINING ONLY ELEMENTSSELECTED FROM THE GROUP CONSISTING OF CARBON, HYDROGEN, OXYGEN, SULFUR,SELENIUM, AND TELLURIUM, AND (2) A PHOSPHORUS SULFIDE SELECTED FROM THEGROUP CONSISTING OF P2S5 AND P4S7, SAID PRODUCT BEING PREPARED BYHEATING FROM ABOUT 0.5 TO ABOUT 10 MOLES OF SAID COMPOUND PER MOLE OFSAID SULFIDE TO A TEMPERATURE AT WHICH HYDROGEN SULFIDE IS RELEASEDM,SAID METALLIC DERIVATIVE BEING PREPARED BY REACTING SAID PRODUCT AT ATEMPERATURE IN THJE RANGE OF ABOUT 180 TO 350*F. WITH AN AMOUNT OF AMETALLIC BASE SELECTED FROM THE GROUP CONSISTING OF OXIDES, HYDROXIDES,AND CARBONATES SUFFICIENT TO NEUTRALIZE AT LEAST A PART OF THE ACIDITYOF SAID PRODUCT; SAID METALLIC DERIVATIVE BEING PRESENT IN SAID FUEL INAMOUNT SUCH THAT THE PHOSPHORUS-TO-LEAD ATOM RATIO IS FROM ABOUT 0.02/3TO ABOUT 1.6/3.